ON THE CRYSTALLINE SLAGS. 369 
14. Anatysis. By J.P. 
This slag was found to contain the same constituents as the one preceding, 
and the analysis was conducted in a similar manner. 
1. Weight of slag 21:00 grains. 
2. Silica 5°01 grains. 
3. Total amount of iron obtained as Fe? O% 14°44. 
The oxide of iron in this case after boiling with KO twice, was redissolved 
in HCl and precipitated by hydrosulphate of ammonia. 
4. Oxide of manganese 1°39. The manganese was precipitated as MnO? 
_ by chlorine and ammonia. 
5. Alumina with phosphoric acid 1°87. The Al? O° was precipitated from 
a solution containing much more P? O than required for saturation, for the 
greater part of the P? O° had been dissolved out of the iron precipitate by 
KO. This fact was confirmed in another case by dissolving the oxide of 
iron after treatment by KO in HCl and digesting with excess of hydro- 
sulphate of ammonia, and testing the filtrate for P?O%. Admitting the 
phosphate of alumina, as precipitated by ammonia, to be 4Al? O3, 3P2 05 
(Rammelsberg, Rapport Annuel, Berzelius, 7*™¢ année, p. 127), the calcu- 
lated proportion of alumina is 0°91. 
6. Sulphate of lime 0°136. 
7. Phosphate of magnesia 0°139. 
8. Sulphur. The observations upon this element in the preceding analysis 
exactly apply to the present. 26:14 grains of slag were fused with 50 of 
nitrate of potass and 100 of the carbonate of potass-soda mixture. Sulphate 
of baryta 0°44. 
9. Sesquioxide of iron. 
1. By chloride of gold and sodium process. Weighed roughly 10 grains. 
Proceeded precisely as in the former analysis. Metallic gold 3:32. 
Total quantity of iron as Fe? O, 5°85. 
2. By Fuchs’s method with pure copper. The necessary precautions 
concerning the exclusion of air during solution, &c. by carbonic 
acid, were carefully attended to. The copper was left in the solu- 
tion during several days, until the latter had become colourless. 
Weight of slag 25°83 grs. A piece of electrotype sheet-copper was 
used; before immersion it weighed 18-176, afterwards 15°815 grs. 
Fe? O83 per cent. by the first method ...... 22°65 
Ditto second versa cay eae 
But the slag contains 0°23 per cent. of sulphur, which corresponds 
to 1:12 per cent. of Fe O%. From the preceding data the following 
results are obtained :-— 
Peas. Pe Ors ales 39°83 
Fe as Fe? OS8 .......... 23°75 
Feas FeS............ 0°62 
10. Phosphoric acid. 
1. By the tartaric acid process. Weight of slag 25:83. The solution 
used in the Fe* OS determination by Cu was employed. The 
phosphate of ammonia and magnesia having a brown colour, it 
was redissolved and reprecipitated by ammonia. Phosphate of 
magnesia 2°76. 
2. The solution obtained in the sulphur determination was also em- 
ployed. Weight of slag 26:14. Phosphate of magnesia 2°66. 
P? O° per cent. by the first method .... 6°40 
Ditto second cece G45 
Wears asin igias S96 Mbs eee ye Le eae GMD 
